Near-Infrared Tissue Oxygenation Provides Incremental Prognostic Value Beyond the Ankle-Brachial Index Following Lower-Extremity Endovascular Revascularization in Patients with Peripheral Artery Disease and Chronic Limb-Threatening Ischemia

Roie Feinsod ^1,2 Boris Khaitovitch ^1,2 Daniel Raskin ³ Daniel Silverberg ^1,4 Moshe Halak ^1,4 Larisa Gorenstein ^1,2 Sasan Partovi ³ Israel Cohen ^1,2

¹Grey Faculty of Medicine, Tel Aviv University, Israel
²Division of Diagnostic Imaging, Sheba Medical Center, Israel
³Division of Interventional Radiology, Cleveland Clinic, United States
⁴Department of Vascular Surgery, Sheba Medical Center, Israel

Background: Near-infrared (NIR) imaging is a noncontact technique that estimates microvascular tissue oxygen saturation (StO2) and may complement the ankle-brachial index (ABI), the standard hemodynamic test for peripheral artery disease (PAD). We assessed whether periprocedural NIR-derived StO2 adds prognostic information beyond ABI after endovascular revascularization.

Methods: In this single-center retrospective cohort study, 55 limbs in 51 patients with PAD or chronic limb-threatening ischemia (CLTI) underwent endovascular revascularization. Dorsal and plantar foot StO2 was measured with a noncontact multispectral NIR camera (SnapshotNIR, Kent Imaging) within 5 minutes before and after the procedure. StO2 values were derived from region-of-interest analysis of the images, and ABI was obtained periprocedurally. Outcomes were target-limb reintervention, amputation, and all-cause mortality. Discrimination was assessed using area under the curve (AUC), and incremental prognostic value over ABI was tested with nested logistic regression.

Results: Median follow-up was 17.0 months. ABI and dorsal StO2 increased significantly after revascularization (both p<0.001); plantar StO2 did not change significantly (p=0.139). Post-procedural plantar StO2 best discriminated reintervention (AUC 0.80) and significantly improved model fit beyond ABI (p=0.009). The change in plantar StO2 was the strongest predictor of mortality (AUC 0.79; p=0.006), while post-procedural dorsal StO2 added modest but significant value for amputation risk (AUC 0.70; p=0.044).Conclusions: Periprocedural NIR imaging adds prognostic value beyond ABI for reintervention, amputation, and mortality after endovascular revascularization. Because it is acquired at the bedside in real time, NIR imaging could also help guide intraprocedural decisions and support post-procedural risk stratification in PAD/CLTI.